The woman, identified as Koel Saha, was pillion riding a bike which was being checked by traffic sergeant B S Dubey at around 8.40 PM and a cab was behind the stationary bike.
Suddenly a speeding mini truck rammed into the rear of the cab which lurched forward and struck the bike which in turn hit the sergeant and two constables on duty.
Police said Koel, who was sitting on the bike, fell down due to the impact and was injured. She was declared dead on arrival when brought to SSKM Hospital.
Sergeant Dubey was admitted to hospital with major injury in his leg while the constables Ayub Ali Khan and Manoj Tokno were released after providing first aid.
The bike rider Umesh Ray and the cab driver were safe.
The driver of the mini truck managed to flee.